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Replacement parts for WHIRLPOOL GY398LXPB00 | AppliancePartsPros.com
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Cannot say whether the control board or the control panel is at fault.
I would try the below Connector cleaning first.
The problem is I cannot find any info on the keyboard pinouts so have no way to check it other than visually.
Your problem can be caused by either, though since it has changed it's symptoms I would go with the control board first but this is just a guess.
Also I am sort of relying on the fact that a keyboard error never came up.
You could try to get into and run the diagnostics.
I am assuming that you have already removed power from the unit and tried it and the control did not reset.
Unplug the unit
Open it up
Remove the ribbon cable from the keypad to the control board at the control board.
Clean the edge connector.
If it is the type where there is not a connector just the insulation is removed, it can be cleaned with a pencil eraser. Do not use an ink eraser as it is too abrasive.
Check the tracks in the ribbon cable for hairline cracks. A magnifying glass helps here.
Would not hurt to clean the connector on the board. Use electronics contact cleaner or isopropyl alcohol and a tooth brush. Be gentle and do not reconnect till all the solvent evaporates.
Reconnect everything and give it a try.